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Toshiki Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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effect of Plantarflexion resistance of an ankle foot orthosis on ankle and knee joint power during gait in individuals post stroke
Journal of Biomechanics, 2018Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Grace Hunt, Bo K ForemanAbstract:Abstract Plantarflexion resistance of an ankle-foot orthosis (AFO) plays an important role to prevent foot-drop, but its impact on push-off has not been well investigated in individuals post-stroke. The aim of this study was to investigate the effect of Plantarflexion resistance of an articulated AFO on ankle and knee joint power of the limb wearing the AFO in individuals post-stroke. Gait analysis was performed on 10 individuals with chronic stroke using a Vicon 3-dimensional motion capture system and a Bertec split-belt instrumented treadmill. They walked on the treadmill under 4 Plantarflexion resistance levels (S1
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reduction of genu recurvatum through adjustment of Plantarflexion resistance of an articulated ankle foot orthosis in individuals post stroke
Clinical Biomechanics, 2016Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background Genu recurvatum (knee hyperextension) is a common issue for individuals post-stroke. Ankle-foot orthoses are used to improve genu recurvatum, but evidence is limited concerning their effectiveness. Therefore, the aim of this study was to investigate the effect of changing the Plantarflexion resistance of an articulated ankle-foot orthosis on genu recurvatum in patients post-stroke. Methods Gait analysis was performed on 6 individuals post-stroke with genu recurvatum using an articulated ankle-foot orthosis whose Plantarflexion resistance was adjustable at four levels. Gait data were collected using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Gait parameters were extracted and plotted for each subject under the four Plantarflexion resistance conditions of the ankle-foot orthosis. Gait parameters included: a) peak ankle Plantarflexion angle, b) peak ankle dorsiflexion moment, c) peak knee extension angle and d) peak knee flexion moment. A non-parametric Friedman test was performed followed by a post-hoc Wilcoxon Signed-Rank test for statistical analyses. Findings All the gait parameters demonstrated statistically significant differences among the four resistance conditions of the AFO. Increasing the amount of Plantarflexion resistance of the ankle-foot orthosis generally reduced genu recurvatum in all subjects. However, individual analyses showed that the responses to the changes in the Plantarflexion resistance of the AFO were not necessarily linear, and appear unique to each subject. Interpretations The Plantarflexion resistance of an articulated AFO should be adjusted to improve genu recurvatum in patients post-stroke. Future studies should investigate what clinical factors would influence the individual differences.
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direct measurement of Plantarflexion resistive moments and angular positions of an articulated ankle foot orthosis while walking in individuals post stroke a preliminary study
Journal of Rehabilitation and Assistive Technologies Engineering, 2016Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Lucas S Lincoln, Fan Gao, Bo K ForemanAbstract:The Plantarflexion resistive moments of an articulated ankle-foot orthosis play an important role in improving gait in individuals post stroke. However, the evidence regarding their magnitude required from the articulated ankle-foot orthosis to improve walking is still limited. Therefore, the primary aim of this study was to directly measure the Plantarflexion resistive moments and the joint angular positions while walking using a prototype instrumented articulated ankle-foot orthosis in five individuals post stroke. The secondary aim was to investigate their moment-angle relationship by changing its preset Plantarflexion stiffness. Each subject was fitted with the instrumented articulated ankle-foot orthosis and walked on a treadmill under four different preset Plantarflexion stiffness conditions (0.35 N·m/°, 0.51 N·m/°, 0.87 N·m/°, and 1.27 N·m/°). For each subject, the Plantarflexion resistive moments and the joint angular positions of five continuous gait cycles were extracted and averaged for each condition. Data were plotted and presented as case series. Both Plantarflexion resistive moments and joint angular positions of the ankle-foot orthosis changed according to the preset Plantarflexion stiffness in all subjects. Using the instrumented articulated ankle-foot orthosis could potentially advance the understanding of the biomechanics of an ankle-foot orthosis, as well as contribute to more evidence-based orthotic care of patients.
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the effect of changing Plantarflexion resistive moment of an articulated ankle foot orthosis on ankle and knee joint angles and moments while walking in patients post stroke
Clinical Biomechanics, 2015Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background The adjustment of Plantarflexion resistive moment of an articulated ankle–foot orthosis is considered important in patients post stroke, but the evidence is still limited. Therefore, the aim of this study was to investigate the effect of changing the Plantarflexion resistive moment of an articulated ankle–foot orthosis on ankle and knee joint angles and moments in patients post stroke. Methods Gait analysis was performed on 10 subjects post stroke under four different Plantarflexion resistive moment conditions using a newly designed articulated ankle–foot orthosis. Data were recorded using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings The ankle and knee sagittal joint angles and moments were significantly affected by the amount of Plantarflexion resistive moment of the ankle–foot orthosis. Increasing the Plantarflexion resistive moment of the ankle–foot orthosis induced significant decreases both in the peak ankle Plantarflexion angle (P Interpretation These results suggest an important link between the kinematic/kinetic parameters of the lower-limb joints and the Plantarflexion resistive moment of an articulated ankle–foot orthosis. A future study should be performed to clarify their relationship further so that the practitioners may be able to use these parameters as objective data to determine an optimal Plantarflexion resistive moment of an articulated ankle–foot orthosis for improved orthotic care in individual patients.
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the effect of ankle foot orthosis Plantarflexion stiffness on ankle and knee joint kinematics and kinetics during first and second rockers of gait in individuals with stroke
Clinical Biomechanics, 2014Co-Authors: Madeline L Singer, Michael S Orendurff, Toshiki Kobayashi, Lucas S Lincoln, Bo K ForemanAbstract:Abstract Background Stiffness of an ankle–foot orthosis plays an important role in improving gait in patients with a history of stroke. To address this, the aim of this case series study was to determine the effect of increasing Plantarflexion stiffness of an ankle–foot orthosis on the sagittal ankle and knee joint angle and moment during the first and second rockers of gait. Methods Gait data were collected in 5 subjects with stroke at a self-selected walking speed under two Plantarflexion stiffness conditions (0.4 Nm/° and 1.3 Nm/°) using a stiffness-adjustable experimental ankle–foot orthosis on a Bertec split-belt fully instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings By increasing the Plantarflexion stiffness of the ankle–foot orthosis, peak Plantarflexion angle of the ankle was reduced and peak dorsiflexion moment was generally increased in the first rocker as hypothesized. Two subjects demonstrated increases in both peak knee flexion angle and peak knee extension moment in the second rocker as hypothesized. The two subjects exhibited minimum contractility during active Plantarflexion, while the other three subjects could actively plantarflex their ankle joint. Interpretation It was suggested that those with the decreased ability to actively plantarflex their ankle could not overcome excessive Plantarflexion stiffness at initial contact of gait, and as a result exhibited compensation strategies at the knee joint. Providing excessively stiff ankle–foot orthoses might put added stress on the extensor muscles of the knee joint, potentially creating fatigue and future pathologies in some patients with stroke.
Bo K Foreman - One of the best experts on this subject based on the ideXlab platform.
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effect of Plantarflexion resistance of an ankle foot orthosis on ankle and knee joint power during gait in individuals post stroke
Journal of Biomechanics, 2018Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Grace Hunt, Bo K ForemanAbstract:Abstract Plantarflexion resistance of an ankle-foot orthosis (AFO) plays an important role to prevent foot-drop, but its impact on push-off has not been well investigated in individuals post-stroke. The aim of this study was to investigate the effect of Plantarflexion resistance of an articulated AFO on ankle and knee joint power of the limb wearing the AFO in individuals post-stroke. Gait analysis was performed on 10 individuals with chronic stroke using a Vicon 3-dimensional motion capture system and a Bertec split-belt instrumented treadmill. They walked on the treadmill under 4 Plantarflexion resistance levels (S1
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reduction of genu recurvatum through adjustment of Plantarflexion resistance of an articulated ankle foot orthosis in individuals post stroke
Clinical Biomechanics, 2016Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background Genu recurvatum (knee hyperextension) is a common issue for individuals post-stroke. Ankle-foot orthoses are used to improve genu recurvatum, but evidence is limited concerning their effectiveness. Therefore, the aim of this study was to investigate the effect of changing the Plantarflexion resistance of an articulated ankle-foot orthosis on genu recurvatum in patients post-stroke. Methods Gait analysis was performed on 6 individuals post-stroke with genu recurvatum using an articulated ankle-foot orthosis whose Plantarflexion resistance was adjustable at four levels. Gait data were collected using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Gait parameters were extracted and plotted for each subject under the four Plantarflexion resistance conditions of the ankle-foot orthosis. Gait parameters included: a) peak ankle Plantarflexion angle, b) peak ankle dorsiflexion moment, c) peak knee extension angle and d) peak knee flexion moment. A non-parametric Friedman test was performed followed by a post-hoc Wilcoxon Signed-Rank test for statistical analyses. Findings All the gait parameters demonstrated statistically significant differences among the four resistance conditions of the AFO. Increasing the amount of Plantarflexion resistance of the ankle-foot orthosis generally reduced genu recurvatum in all subjects. However, individual analyses showed that the responses to the changes in the Plantarflexion resistance of the AFO were not necessarily linear, and appear unique to each subject. Interpretations The Plantarflexion resistance of an articulated AFO should be adjusted to improve genu recurvatum in patients post-stroke. Future studies should investigate what clinical factors would influence the individual differences.
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direct measurement of Plantarflexion resistive moments and angular positions of an articulated ankle foot orthosis while walking in individuals post stroke a preliminary study
Journal of Rehabilitation and Assistive Technologies Engineering, 2016Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Lucas S Lincoln, Fan Gao, Bo K ForemanAbstract:The Plantarflexion resistive moments of an articulated ankle-foot orthosis play an important role in improving gait in individuals post stroke. However, the evidence regarding their magnitude required from the articulated ankle-foot orthosis to improve walking is still limited. Therefore, the primary aim of this study was to directly measure the Plantarflexion resistive moments and the joint angular positions while walking using a prototype instrumented articulated ankle-foot orthosis in five individuals post stroke. The secondary aim was to investigate their moment-angle relationship by changing its preset Plantarflexion stiffness. Each subject was fitted with the instrumented articulated ankle-foot orthosis and walked on a treadmill under four different preset Plantarflexion stiffness conditions (0.35 N·m/°, 0.51 N·m/°, 0.87 N·m/°, and 1.27 N·m/°). For each subject, the Plantarflexion resistive moments and the joint angular positions of five continuous gait cycles were extracted and averaged for each condition. Data were plotted and presented as case series. Both Plantarflexion resistive moments and joint angular positions of the ankle-foot orthosis changed according to the preset Plantarflexion stiffness in all subjects. Using the instrumented articulated ankle-foot orthosis could potentially advance the understanding of the biomechanics of an ankle-foot orthosis, as well as contribute to more evidence-based orthotic care of patients.
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the effect of changing Plantarflexion resistive moment of an articulated ankle foot orthosis on ankle and knee joint angles and moments while walking in patients post stroke
Clinical Biomechanics, 2015Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background The adjustment of Plantarflexion resistive moment of an articulated ankle–foot orthosis is considered important in patients post stroke, but the evidence is still limited. Therefore, the aim of this study was to investigate the effect of changing the Plantarflexion resistive moment of an articulated ankle–foot orthosis on ankle and knee joint angles and moments in patients post stroke. Methods Gait analysis was performed on 10 subjects post stroke under four different Plantarflexion resistive moment conditions using a newly designed articulated ankle–foot orthosis. Data were recorded using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings The ankle and knee sagittal joint angles and moments were significantly affected by the amount of Plantarflexion resistive moment of the ankle–foot orthosis. Increasing the Plantarflexion resistive moment of the ankle–foot orthosis induced significant decreases both in the peak ankle Plantarflexion angle (P Interpretation These results suggest an important link between the kinematic/kinetic parameters of the lower-limb joints and the Plantarflexion resistive moment of an articulated ankle–foot orthosis. A future study should be performed to clarify their relationship further so that the practitioners may be able to use these parameters as objective data to determine an optimal Plantarflexion resistive moment of an articulated ankle–foot orthosis for improved orthotic care in individual patients.
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the effect of ankle foot orthosis Plantarflexion stiffness on ankle and knee joint kinematics and kinetics during first and second rockers of gait in individuals with stroke
Clinical Biomechanics, 2014Co-Authors: Madeline L Singer, Michael S Orendurff, Toshiki Kobayashi, Lucas S Lincoln, Bo K ForemanAbstract:Abstract Background Stiffness of an ankle–foot orthosis plays an important role in improving gait in patients with a history of stroke. To address this, the aim of this case series study was to determine the effect of increasing Plantarflexion stiffness of an ankle–foot orthosis on the sagittal ankle and knee joint angle and moment during the first and second rockers of gait. Methods Gait data were collected in 5 subjects with stroke at a self-selected walking speed under two Plantarflexion stiffness conditions (0.4 Nm/° and 1.3 Nm/°) using a stiffness-adjustable experimental ankle–foot orthosis on a Bertec split-belt fully instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings By increasing the Plantarflexion stiffness of the ankle–foot orthosis, peak Plantarflexion angle of the ankle was reduced and peak dorsiflexion moment was generally increased in the first rocker as hypothesized. Two subjects demonstrated increases in both peak knee flexion angle and peak knee extension moment in the second rocker as hypothesized. The two subjects exhibited minimum contractility during active Plantarflexion, while the other three subjects could actively plantarflex their ankle joint. Interpretation It was suggested that those with the decreased ability to actively plantarflex their ankle could not overcome excessive Plantarflexion stiffness at initial contact of gait, and as a result exhibited compensation strategies at the knee joint. Providing excessively stiff ankle–foot orthoses might put added stress on the extensor muscles of the knee joint, potentially creating fatigue and future pathologies in some patients with stroke.
Tadashi Yasui - One of the best experts on this subject based on the ideXlab platform.
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effects of an ankle foot orthosis with oil damper on muscle activity in adults after stroke
Gait & Posture, 2011Co-Authors: Koji Ohata, Tadashi Yasui, Tadao Tsuboyama, Noriaki IchihashiAbstract:Abstract Background and objective An ankle-foot orthosis with an oil damper (AFO-OD) was developed to resist Plantarflexion motion, thereby improving hemiplegic gait performance. The purpose of this study was to determine the effect of AFO-OD on muscle activity during the gait cycle in individuals affected by stroke. Methods Electromyography (EMG) was used to assess gait at a self-selected speed while wearing an AFO-OD or an AFO with a Plantarflexion stop (AFO-PS) worn on the affected side in 11 stroke survivors and on the right side in 11 age-matched healthy adults. EMG signals were obtained from the tibialis anterior (TA), gastrocnemius (GAS), and soleus (SOL) muscles. In addition, the ankle joint angle under both braces and the Plantarflexion resistance torque (PFRT) under AFO-OD were monitored. Results Peak PFRT under AFO-OD was observed during the loading response phase (LRP) in both groups. AFO-OD promoted adequate Plantarflexion during LRP in the stroke group, whereas AFO-PS did not. Compared with the AFO-PS, the AFO-OD significantly reduced GAS EMG amplitude during LRP in the stroke group, which was significantly correlated with peak PFRT during LRP. Conclusion AFO-OD assisted the “heel rocker function” and reduced GAS muscle EMG amplitude during LRP.
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kinematic effects on gait of a newly designed ankle foot orthosis with oil damper resistance a case series of 2 patients with hemiplegia
Archives of Physical Medicine and Rehabilitation, 2005Co-Authors: Osamu Yokoyama, Hironobu Sashika, Akiyoshi Hagiwara, Sumiko Yamamoto, Tadashi YasuiAbstract:Abstract Yokoyama O, Sashika H, Hagiwara A, Yamamoto S, Yasui T. Kinematic effects on gait of a newly designed ankle-foot orthosis with oil damper resistance: a case series of 2 patients with hemiplegia. The ankle joint of ankle-foot orthoses (AFOs) should restrict Plantarflexion to prevent foot drop during the swing phase. However, excessive Plantarflexion resistance causes excessive knee flexion during the stance phase. Plantarflexion resistive moment should be easily adjustable according to the gait ability of patients with hemiplegia. Because it is difficult to adjust Plantarflexion resistive moment exactly, we developed an AFO with an oil damper. It is a small shock absorber that utilizes hydraulic resistance. The oil damper generates a resistive moment to the Plantarflexion rotation of the ankle joint at the initial stance phase. The magnitude of the Plantarflexion resistive moment at the heel strike can be easily adjusted to accommodate each patient’s condition by simply turning an adjustment screw. We used a gait analysis system to compare the gait of 2 hemiplegic patients while they were wearing either the AFO with the oil damper or the AFO with the Plantarflexion stop. The AFO with the oil damper achieved sufficient Plantarflexion of the ankle and mild flexion of the knee by adjusting a proper Plantarflexion resistive moment during initial stance phase, and provided a more comfortable gait than did the AFOs with a Plantarflexion stop.
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kinematic effects on gait of a newly designed ankle foot orthosis with oil damper resistance a case series of 2 patients with hemiplegia
Archives of Physical Medicine and Rehabilitation, 2005Co-Authors: Osamu Yokoyama, Hironobu Sashika, Akiyoshi Hagiwara, Sumiko Yamamoto, Tadashi YasuiAbstract:The ankle joint of ankle-foot orthoses (AFOs) should restrict Plantarflexion to prevent foot drop during the swing phase. However, excessive Plantarflexion resistance causes excessive knee flexion during the stance phase. Plantarflexion resistive moment should be easily adjustable according to the gait ability of patients with hemiplegia. Because it is difficult to adjust Plantarflexion resistive moment exactly, we developed an AFO with an oil damper. It is a small shock absorber that utilizes hydraulic resistance. The oil damper generates a resistive moment to the Plantarflexion rotation of the ankle joint at the initial stance phase. The magnitude of the Plantarflexion resistive moment at the heel strike can be easily adjusted to accommodate each patient's condition by simply turning an adjustment screw. We used a gait analysis system to compare the gait of 2 hemiplegic patients while they were wearing either the AFO with the oil damper or the AFO with the Plantarflexion stop. The AFO with the oil damper achieved sufficient Plantarflexion of the ankle and mild flexion of the knee by adjusting a proper Plantarflexion resistive moment during initial stance phase, and provided a more comfortable gait than did the AFOs with a Plantarflexion stop.
Stephen W Hutchins - One of the best experts on this subject based on the ideXlab platform.
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the effect of varying the Plantarflexion resistance of an ankle foot orthosis on knee joint kinematics in patients with stroke
Gait & Posture, 2013Co-Authors: Toshiki Kobayashi, Aaron K L Leung, Yasushi Akazawa, Stephen W HutchinsAbstract:Ankle-foot orthoses (AFOs) can improve gait in patients with hemiplegia. However, it is anecdotally known that excessive Plantarflexion resistance of an AFO could induce undesired knee flexion at early stance. The aim of this study was to systematically investigate the effect of varying the degrees of Plantarflexion resistance of an AFO on knee flexion angles at early stance in five subjects with chronic stroke who demonstrated two clear knee flexion peaks at early stance and swing. Each subject wore an experimental AFO constructed with an oil-damper type ankle joint and was instructed to walk at their self-selected walking speed under five Plantarflexion resistance conditions. The sagittal plane ankle and knee joint kinematics and gait speed were analyzed using a 3-D Motion Analysis System. A number of significant differences (P<0.005) in maximum knee flexion angles at early stance amongst different Plantarflexion resistance conditions were revealed. The knee flexion angle was 23.80 (3.25) degrees under the free hinge joint condition (condition 1), while that was 26.09 (3.79) degrees under the largest resistance condition (condition 5). It was therefore demonstrated that increasing the Plantarflexion resistance of an AFO would induce more knee flexion at early stance phase in patients with stroke.
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the effect of varying the Plantarflexion resistance of an ankle foot orthosis on knee joint kinematics in patients with stroke
Gait & Posture, 2013Co-Authors: Toshiki Kobayashi, Aaron K L Leung, Yasushi Akazawa, Stephen W HutchinsAbstract:Abstract Ankle-foot orthoses (AFOs) can improve gait in patients with hemiplegia. However, it is anecdotally known that excessive Plantarflexion resistance of an AFO could induce undesired knee flexion at early stance. The aim of this study was to systematically investigate the effect of varying the degrees of Plantarflexion resistance of an AFO on knee flexion angles at early stance in five subjects with chronic stroke who demonstrated two clear knee flexion peaks at early stance and swing. Each subject wore an experimental AFO constructed with an oil-damper type ankle joint and was instructed to walk at their self-selected walking speed under five Plantarflexion resistance conditions. The sagittal plane ankle and knee joint kinematics and gait speed were analyzed using a 3-D Motion Analysis System. A number of significant differences ( P
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design of a stiffness adjustable ankle foot orthosis and its effect on ankle joint kinematics in patients with stroke
Gait & Posture, 2011Co-Authors: Toshiki Kobayashi, Aaron K L Leung, Yasushi Akazawa, Stephen W HutchinsAbstract:Ankle-foot orthoses (AFOs) are commonly prescribed to improve gait. The stiffness of an AFO is central for successful prescription; however, the recommended level of stiffness is currently based on the experience of clinicians. Therefore, the aim of this study was to design an experimental AFO (EAFO) whose stiffness was adjustable using commercially available oil-damper joints, and to demonstrate its potential capability in investigating the effects of altering AFO stiffness on gait. The influence of the EAFO stiffness on ankle joint kinematics in sagittal plane was evaluated in 10 patients with stroke by altering the stiffness of its oil-damper- type orthotic ankle joints using the four levels pre-set and defined by the manufacturer in dorsi- and Plantarflexion directions independently. The mean peak Plantarflexion angle was reduced by 105%, showing a change from 8.18 (3.14) degrees of Plantarflexion to 0.38 (4.17) degrees of dorsiflexion, whilst the mean peak dorsiflexion angle was reduced by 44%, showing a change from 11.46 (5.57) degrees of dorsiflexion to 6.47 (5.23) degrees of dorsiflexion by altering the EAFO stiffness. The EAFO would therefore serve as a convenient tool when investigating the influence of AFO stiffness on gait in both clinical and research settings.
Madeline L Singer - One of the best experts on this subject based on the ideXlab platform.
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effect of Plantarflexion resistance of an ankle foot orthosis on ankle and knee joint power during gait in individuals post stroke
Journal of Biomechanics, 2018Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Grace Hunt, Bo K ForemanAbstract:Abstract Plantarflexion resistance of an ankle-foot orthosis (AFO) plays an important role to prevent foot-drop, but its impact on push-off has not been well investigated in individuals post-stroke. The aim of this study was to investigate the effect of Plantarflexion resistance of an articulated AFO on ankle and knee joint power of the limb wearing the AFO in individuals post-stroke. Gait analysis was performed on 10 individuals with chronic stroke using a Vicon 3-dimensional motion capture system and a Bertec split-belt instrumented treadmill. They walked on the treadmill under 4 Plantarflexion resistance levels (S1
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reduction of genu recurvatum through adjustment of Plantarflexion resistance of an articulated ankle foot orthosis in individuals post stroke
Clinical Biomechanics, 2016Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background Genu recurvatum (knee hyperextension) is a common issue for individuals post-stroke. Ankle-foot orthoses are used to improve genu recurvatum, but evidence is limited concerning their effectiveness. Therefore, the aim of this study was to investigate the effect of changing the Plantarflexion resistance of an articulated ankle-foot orthosis on genu recurvatum in patients post-stroke. Methods Gait analysis was performed on 6 individuals post-stroke with genu recurvatum using an articulated ankle-foot orthosis whose Plantarflexion resistance was adjustable at four levels. Gait data were collected using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Gait parameters were extracted and plotted for each subject under the four Plantarflexion resistance conditions of the ankle-foot orthosis. Gait parameters included: a) peak ankle Plantarflexion angle, b) peak ankle dorsiflexion moment, c) peak knee extension angle and d) peak knee flexion moment. A non-parametric Friedman test was performed followed by a post-hoc Wilcoxon Signed-Rank test for statistical analyses. Findings All the gait parameters demonstrated statistically significant differences among the four resistance conditions of the AFO. Increasing the amount of Plantarflexion resistance of the ankle-foot orthosis generally reduced genu recurvatum in all subjects. However, individual analyses showed that the responses to the changes in the Plantarflexion resistance of the AFO were not necessarily linear, and appear unique to each subject. Interpretations The Plantarflexion resistance of an articulated AFO should be adjusted to improve genu recurvatum in patients post-stroke. Future studies should investigate what clinical factors would influence the individual differences.
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direct measurement of Plantarflexion resistive moments and angular positions of an articulated ankle foot orthosis while walking in individuals post stroke a preliminary study
Journal of Rehabilitation and Assistive Technologies Engineering, 2016Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Lucas S Lincoln, Fan Gao, Bo K ForemanAbstract:The Plantarflexion resistive moments of an articulated ankle-foot orthosis play an important role in improving gait in individuals post stroke. However, the evidence regarding their magnitude required from the articulated ankle-foot orthosis to improve walking is still limited. Therefore, the primary aim of this study was to directly measure the Plantarflexion resistive moments and the joint angular positions while walking using a prototype instrumented articulated ankle-foot orthosis in five individuals post stroke. The secondary aim was to investigate their moment-angle relationship by changing its preset Plantarflexion stiffness. Each subject was fitted with the instrumented articulated ankle-foot orthosis and walked on a treadmill under four different preset Plantarflexion stiffness conditions (0.35 N·m/°, 0.51 N·m/°, 0.87 N·m/°, and 1.27 N·m/°). For each subject, the Plantarflexion resistive moments and the joint angular positions of five continuous gait cycles were extracted and averaged for each condition. Data were plotted and presented as case series. Both Plantarflexion resistive moments and joint angular positions of the ankle-foot orthosis changed according to the preset Plantarflexion stiffness in all subjects. Using the instrumented articulated ankle-foot orthosis could potentially advance the understanding of the biomechanics of an ankle-foot orthosis, as well as contribute to more evidence-based orthotic care of patients.
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the effect of changing Plantarflexion resistive moment of an articulated ankle foot orthosis on ankle and knee joint angles and moments while walking in patients post stroke
Clinical Biomechanics, 2015Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background The adjustment of Plantarflexion resistive moment of an articulated ankle–foot orthosis is considered important in patients post stroke, but the evidence is still limited. Therefore, the aim of this study was to investigate the effect of changing the Plantarflexion resistive moment of an articulated ankle–foot orthosis on ankle and knee joint angles and moments in patients post stroke. Methods Gait analysis was performed on 10 subjects post stroke under four different Plantarflexion resistive moment conditions using a newly designed articulated ankle–foot orthosis. Data were recorded using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings The ankle and knee sagittal joint angles and moments were significantly affected by the amount of Plantarflexion resistive moment of the ankle–foot orthosis. Increasing the Plantarflexion resistive moment of the ankle–foot orthosis induced significant decreases both in the peak ankle Plantarflexion angle (P Interpretation These results suggest an important link between the kinematic/kinetic parameters of the lower-limb joints and the Plantarflexion resistive moment of an articulated ankle–foot orthosis. A future study should be performed to clarify their relationship further so that the practitioners may be able to use these parameters as objective data to determine an optimal Plantarflexion resistive moment of an articulated ankle–foot orthosis for improved orthotic care in individual patients.
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the effect of ankle foot orthosis Plantarflexion stiffness on ankle and knee joint kinematics and kinetics during first and second rockers of gait in individuals with stroke
Clinical Biomechanics, 2014Co-Authors: Madeline L Singer, Michael S Orendurff, Toshiki Kobayashi, Lucas S Lincoln, Bo K ForemanAbstract:Abstract Background Stiffness of an ankle–foot orthosis plays an important role in improving gait in patients with a history of stroke. To address this, the aim of this case series study was to determine the effect of increasing Plantarflexion stiffness of an ankle–foot orthosis on the sagittal ankle and knee joint angle and moment during the first and second rockers of gait. Methods Gait data were collected in 5 subjects with stroke at a self-selected walking speed under two Plantarflexion stiffness conditions (0.4 Nm/° and 1.3 Nm/°) using a stiffness-adjustable experimental ankle–foot orthosis on a Bertec split-belt fully instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings By increasing the Plantarflexion stiffness of the ankle–foot orthosis, peak Plantarflexion angle of the ankle was reduced and peak dorsiflexion moment was generally increased in the first rocker as hypothesized. Two subjects demonstrated increases in both peak knee flexion angle and peak knee extension moment in the second rocker as hypothesized. The two subjects exhibited minimum contractility during active Plantarflexion, while the other three subjects could actively plantarflex their ankle joint. Interpretation It was suggested that those with the decreased ability to actively plantarflex their ankle could not overcome excessive Plantarflexion stiffness at initial contact of gait, and as a result exhibited compensation strategies at the knee joint. Providing excessively stiff ankle–foot orthoses might put added stress on the extensor muscles of the knee joint, potentially creating fatigue and future pathologies in some patients with stroke.